Assessing release protocols for Canada lynx reintroduction in colorado

Reintroductions are a common strategy to restore ecosystem integrity, especially when top predators are involved. Reintroductions are often time consuming, expensive, and controversial, and thus understanding what aspects are important for a successful program is needed. Focusing on the example of the reintroduction of Canada lynx (Lynx canadensis) to Colorado, we investigated how different release protocols (RP) affected mortality within the first year post-release. We found that average monthly mortality in the study area during the first year decreased with time in captivity from 0.205 (95% CI = 0.069, 0.475) for lynx having spent up to 7 days in captivity to 0.028 (95% CI = 0.012, 0.064) for lynx spending >45 days in captivity before release. Our results also suggest that keeping lynx in captivity beyond 5–6 weeks accrued little benefit in terms of monthly survival. We found that, on a monthly average basis, lynx were as likely to move out (P = 0.196, SE = 0.032) as well as back onto (P = 0.143, SE = 0.034) the reintroduction area during the first year after release. Mortality was 1.6 times greater outside of the study area, suggesting that permanent emigration and differential mortality rates on and off reintroduction areas should be factored into sample size calculations for an effective reintroduction effort. A post-release monitoring plan is critical to providing information to assess aspects of RP and to improve survival of individuals. Future lynx and other carnivore reintroductions may use our results to help design reintroduction programs including both the release and post-release monitoring protocols. © 2011 The Wildlife Society.     

Release density,efficiency and disappearance ofTrichogramma nubilale for control of European corn borer

We evaluated how manyTrichogramma nubilale should be released at a single location to controlOstrinia nubilalis in sweet corn. Six 8.6×16 m plots received 18.4 to 2 090 ΦΦT. nubilale/SAI when plants were in the mid to late whorl stage, where SAI, surface area index, is the plant surface area/m². To evaluate the potential control by our releases, we exposed laboratory-rearedO. nubilalis egg masses to the released parasitoids at 4 times after the release. When an egg mass was parasitized byT. nubilale, 75.7% of the eggs in the egg mass were parasitized. We developed an equation to estimate the percent of egg masses that a single female was expected to parasitize in a day (efficiency of parasitism) and female disappearance (death and dispersal) rates, if both were constant during our experiment. The exponential disappearance rate was −0.52±0.03 day⁻¹, which implied that 40% of the remaining ΦΦ disappeared per day. The efficiency of parasitism was 0.050% parasitism/Φ/SAI/day, which implied that at least 351,000 ΦΦ/ha would be needed to achieve 90% parasitism. Clearly, forT. nubilale to be a successful biological control agent, efficiency of parasitism must be increased and disappearance rates must be reduced.      

Construction and characterization of a Rhizobium leguminosarum biovar viciae strain designed to assess horizontal gene transfer in the environment

Abstract An integration vector was developed which inserts cloned DNA in a non-essential site of the Rhizobium leguminosarum biovar viciae chromosome. The expression of integrated genes is under the control of the constitutive neomycin phosphotransferase II ( npt II) promotor of transposon Tn5. The design of the vector ensures that loss of vector sequences can be detected, enabling selection of progeny containing only the requisite DNA. The newly constructed vector was employed to insert the Escherichia coli gusA gene conferring GUS activity into R. leguminosarum bv. viciae strain LRS39401 which is cured of its symbiotic plasmid (pSym). One GUS-positive transconjugant, strain CT0370, was shown to have lost all vector sequences. Conjugal transfer of pSym2004 (a Tn5-tagged derivative of symbiotic plasmid pRL1JI, which specifies pea nodulation and symbiotic nitrogen fixation) to CT0370, restored the GUS-positive strain's symbiotic proficiency. Strain CT0370 is presently being used in a field release experiment in order to assess the extent of pSym transfer in a natural R. leguminosarum bv. viciae population under environmental conditions.     

Tryptophan Availability Modulates Serotonin Release from Rat Hypothalamic Slices

Application of a novel in vitro experimental system has allowed us to describe the relationship between tryptophan availability and serotonin release from rat hypothalamic slices. Superfusing hypothalamic slices with a physiologic medium containing l-tryptophan (1, 2, 5, or 10 microM) caused dose-dependent elevations in tissue tryptophan levels; the magnitude of the elevations produced by supplementing the medium with less than 5 microM tryptophan was within the physiologic range for rat brain tryptophan levels. Slice serotonin levels rose biphasically as the tryptophan concentration in the medium was increased. Superfusing the slices with medium supplemented with a low tryptophan concentration (1 or 2 microM) caused proportionally greater incremental changes in serotonin levels than the increases caused by further elevating the tryptophan concentration (5 or 10 microM). The spontaneous release of serotonin from the slices exhibited a dose-dependent relationship with the tryptophan concentration of the superfusion medium. Electrically evoked serotonin release, which was calcium-dependent and tetrodotoxin-sensitive, also increased in proportion to the medium tryptophan concentration. These data suggest that the rate at which serotonin is released from hypothalamic nerve terminals is coupled to brain tryptophan levels. Accelerations in hypothalamic serotonin synthesis, caused by elevating brain tryptophan levels, result in proportionate increases in the rates of serotonin release during rest and with membrane depolarization.     

Syntheses of Female Sex Pheromone Analogues of the German Cockroach and Their Biological Activity

Several analogues of 3,1l-dimethyl-2-nonacosanone, one component of the sex pheromone of the German cockroach, were synthesized. Their activity for the male to raise his wings was assayed and summerized in Tables I and II.     

Release of molybdenum co-factor from nitrate reductase and xanthine oxidase by heat treatment

Heat treatment (90 sec at 70°) is shown to convert the bound molybdenum co-factor of tobacco cell-free extracts and bovine milk xanthine oxidase into a form capable of complementing the Neurospora crassa mutant nit-1.In the presence of 1 mM ascorbic acid, 25 mM molybdate and, for plant extracts, sulphydryl group protecting agents, the molybdenum co-factor can survive incubations up to 100° whilst maintaining its biological activity. Especially with plant extracts, the efficiency of heat treatment is considerably higher than that of the acidification procedure which is often utilized for releasing molybdenum co-factor.     

Interaction between the δ-endotoxin produced by Bacillus thuringiensis ssp. entomocidus and liposomes

The δ-endotoxin produced by Bacillus thuringiensis ssp. entomocidus induced the release of encapsulated [¹⁴C]sucrose from reverse-phase vesicles composed of phosphatidylcholine and cholesterol. No such release was detected when the phospholipid component of the vesicles was either phosphatidylethanolamine, phosphatidylglycerol, or sphingomyelin. The toxin-induced release was competitively inhibited by negatively charged organic ions while positively charged organic ions, apart from choline chloride, had no such effect. The existence of a polar head group in the phospholipid as well as intermolecular hydrogen bonding at the membrane surface, was found to be of major importance in the toxin-liposome interaction.     

Comparison of Three Dissolution Apparatuses for Testing Calcium Phosphate Pellets used as Ibuprofen Delivery Systems

Porous calcium phosphate pellets were produced according to two granulation processes (low and high shear wet granulations) and drug loaded with five ibuprofen contents (1.75%, 7%, 12.5%, 22%, and 36%) in order to ensure both bone defect filling and local drug delivery. The drug-release kinetics from the two types of pellets was studied using three dissolution apparatuses: paddle apparatus, reciprocating cylinder, and flow-through cell. The paper compared the three dissolution methods and considered the effect of the granulation process on the ibuprofen-release kinetics. Dissolution data were analyzed using the Weibull function as well as the difference (f1) and similarity (f2) factors. Dissolution kinetics was not influenced by the granulation process, regardless of the dissolution apparatus and of the drug content. The comparison of the three dissolution devices indicated that ibuprofen was released faster from granules loaded with 36% of drug content with the reciprocating apparatus, due to the disintegration of the granules occurring during the dissolution test. For the other drug contents, dissolution profiles were not significantly different from one apparatus to another. However, the flow-through cell seemed to be more suitable for the drug-release study of implantable materials.     

Release of Cholecystokinin-Like Immunoreactivity in the Frontal Cortex of Conscious Rats as Assessed by Transcerebral Microdialysis: Effects of Different Depolarizing Stimuli

Abstract: The release of cholecystokinin-like immunoreactivity (CCK-LI) from the frontal cortex of freely moving rats has been studied using a transcerebral microdialysis technique coupled to a radioimmunoassay procedure. Basal levels of CCK-LI in the dialysate were above detection limits (2.4 ± 0.7 pg/20 min; n = 8). High-K⁺ media evoked CCK-LI overflow in a concentration-dependent manner. The threshold concentration was 50 mM KCI. The peak overflow evoked by 100 mM K⁺ amounted to 42.7 ± 2.8 pg/20 min (n = 6); it was totally Ca²⁺ dependent but insensitive to 1 μM tetrodotoxin. Infusion of 4-aminopyridine (1 mM ; 20 min) evoked an overflow of CCK-LI (32 ± 2.3 pg/ 20 min; n = 4), wnich was totally Ca²⁺ dependent and tetrodotoxin sensitive. Depolarization with 100 μg/ml of veratrine (20 min) provoked a CCK-LI overflow (62.2 ± 10 pg/20 min; n = 6), which was also blocked by tetrodotoxin or by the absence of Ca²⁺ ions. The CCK-LI material collected under basal conditions or during veratrine infusion consisted essentially of CCK octapeptide sulfate. The veratrine-induced CCK-LI overflow did not change significantly when the infusion time was prolonged to 100 min. A second 20-min stimulus with 100 μg/ml of veratrine applied 200 min after a first 20-min stimulus evoked a barely significant CCK-LI overflow. These data suggest that one single 20-min stimulus with 100 μg/ml of veratrine may be sufficient to deplete the CCK-LI releasable stores and that >200 min are required to replenish the depleted CCK-containing vesicles. Taken together the data allow us to conclude that the physiology and the pharmacology of CCK release can be adequately studied in vivo by brain microdialysis.     

Cytopathic Action of Naegleria fowleri Amoebae on Rat Neuroblastoma Target Cells

The axenically cultured, weakly pathogenic Naegleria fowleri LEE and the highly pathogenic, mouse passaged N. fowleri LEEmp are cytopathic for B103 rat nerve cells in culture. Cytopathogenicity was measured by release of radiolabeled rubidium or radiolabeled chromium from B103 target cells. Cytopathogenicity was time-dependent for up to 18 h and dependent upon amoebae effector to nerve cell target ratios of less than 1:1. Release of⁵¹ Cr from B103 cells by either LEE or LEEmp amoebae was enhanced by addition of calcium or magnesium to medium free of these divalent cations but the ion-channel inhibitor, verapamil, or the ionophore A23187 and phorbol myristate acetate did not alter release of ⁵¹ Cr from B103 cells cocultured with the amoebae. Cycloheximide or actinomycin D impaired release of ⁵¹ Cr from B103 target cells injured by either LEE or LEEmp amoebae. Both strains of amoebae were fractionated by glass bead disruption and high speed centrifugation into membrane and soluble fractions. Each fraction was incubated with either ⁸⁶Rb or ⁵¹ Cr labeled nerve cells. The membrane fraction from LEEmp was more active than the soluble fraction in facilitating rubidium and chromium release. In contrast, the soluble fraction from LEE was more active than the membrane fraction in facilitating rubidium release from radiolabeled target cells. The sequential release of ⁸⁶Rb and ⁵¹ Cr from target cells rather than the simultaneous release of the two isotopes indicates that target cell death is due to the release of ions followed later by the release of large macromolecules. The results indicate that N. fowleri amoebae injure nerve cells by two alternate mechanisms, trogocytosis or contact-dependent lysis.